Abstract
BACKGROUND: Internal teat sealants are commonly used at drying off, with or without intramammary antibiotics, to reduce the risk of mastitis. Both full and partial cannula options are available on most teat sealant and antibiotic tubes, but little evidence exists to support the selection of one option over the other. METHODS: A total of 287 Holstein cows from three UK farms were enrolled in the study. Cows were randomly allocated to receive either full or partial insertion of internal teat sealant at drying off (plus the same insertion type of intramammary antibiotic if required by farm protocols). Somatic cell count and clinical mastitis data were collected, along with lactation number and calving season, and analysed using multivariable regression modelling. RESULTS: Insertion type was not associated with high postcalving somatic cell counts (SCCs; >200k cells/mL), new infection rates (low to high SCC change across the dry period), cure rates (high to low SCC change across the dry period) or clinical mastitis cases. LIMITATIONS: Only pedigree Holsteins were included; results in other breeds could differ due to teat size. CONCLUSION: Insertion type was not associated with high SCC or increased postcalving mastitis cases.